Method of making abrasive grinding members



Patented Nov. 22, 1949 I METHOD OF MAKING ABR'ASIVE GRINDING 'MEMBERS Frederick H. Apel, AtholSprings, N. Y.

4 'No2Drawing. Application-February-11,1946,

Serial No. 646,956

2 Claims. (01. 51- 301) This invention relates to a method .of makinggrinding or polishing members, such as wheels or pads-used for-grinding or polishing plastics andsofter metal, suchas lead, solder, white metal, aluminum, brass and magnesium.

I-Ieretofore such members usually comprised a plurality of layers of woven sheets of cotton cloth or felt coated with an abrasive which. is unsatisfactory becausethe same not only became loaded with-particles of metal .or the like which were removed from the article being. groundor polished and thus required frequent dressing andrecoating to restore the grinding or polishing effect, but the same also lacked durability and required frequent :recoating with abrasive in order to maintain the'same in effective condition so .that Work of this'character. was undulyexpensive.

It is the objectof thisinvention to provide method of makinggrindingor polishing wheelsor pads which is strong, durable .and flexible and well suited fordoing work of .this kind and incapable of becoming loaded with'removed particles and also does not require dressing to main.- tain'the same in effective condition.

The principal ingredients in the compound used in this invention and the relative :quantities of the same are as follows:

Wool capable of being felteds ounces Abrasive grains, such as crocus, tripoli, pumice, carborundum or aloxiteof the requisite fineness for therespective work to be done do 3% Glue prefera-bIy made from hides do 4 Water do 5 Skim milk do 4 Glycerine i, do -3t Borax grains 40 Wax, preferably ceresin drams 1 Formaldehyde, 37% or paraformaldehyde either in liquid or powdered form ounces If desired the following constituents in the quantities named may be included in the .compound:

Drams Soap, preferably yellow chips 1 Sugar 1 Into this meltedglu'e the iounces of milk and glycerine are introduced and thoroughly mixed by stirringthese several ingredients.

Thereafter'30rgrains of .borax areadded to the above mentioned mixed and stirredingredients until this'borax is thoroughlydissolved.

.To this .main mixture is next added a previously preparedseparate mixture of ingredients consisting .of the one dram of. wax which has been" meltedat a temperature of about degrees" Fahrenheit, ounce of .milk and the 10 grains of borax, this separate mixture being stirred into the main mixture whilethe combined mixtures arebeingheated in a boiler up to.a temperature of 212 degrees F. and the stirring continued until ebullition .of the combined main and separate mixtureslhas stopped.

Stirring of this totalmixture may be continued until it is of smooth consistency and spreadable like any wood workersglue, and if theiresultant product is found too thick, due to evaporation, thesame may be thinnedto the required consistency'hy the .addition of a suitable amountof water. l

The combined mixture thus far described 0on stitu'tes the. binder or'bondingmedium with which thewoolfiber .andabrasive grains are now mixed so-as .to thoroughly coat the fibers and abrasive grains. In. assembling the several ingredients of this compound the wool fiber is spread in a nutty-state on a warm slab to form a sheet, the abrasive grains are spread over this sheet, and sufiicient of the binding solution is poured on top of this layer to thoroughly wet the fibers and-grains. Thereafter this sheet is folded several'times with a broad. knife to form a plurality of layersand tamped with a suitable tool to .produce an even mixture and felting of the fibers. A layerof the folded mass is then placed in the mold-tandsprayed withformaldehyde and tamped, and thereafter the other layers are successively placed one on. top of another-in themold and each additionallayer issimilarlysprayed with formaldehyde and. tampeduntilthe mold .is filled. The filled-mold is thenwplaced ina chamber heated to about rl-ludegrees tor about five-hours, to cure the mass, and then the compound mass is removed from the mold and allowed to air dry from 12 to 15 hours.

When using sugar and soap as part of the compound, these ingredients are added to the mixture after the introduction of the skim milk, glycerine and 30 grains of ,borax and stirredtherewith until thoroughly dissolved.

The tamping of the mass ing medium and the abrasive grains distributes thebonduniformly K throughout the mass, and also facilitates the felting of the wool fibers, and the heating of the mass at this time accelerates the action of the formaldehyde.

While being cured the mass is shaped by appropriate molds into the form of wheels, blocks, pads, rods or any other desired shape to suit the requirements of the particular work in hand.

In the foregoing compound the action of the glycerine on the glue is to keep the latter from drying out when the same is mixed with milk, borax and wax and treated under heat after formaldehyde is added to the mixture and thus forms a non-tacky and insoluble, but pliable mass which will not get brittle when subjected to a drying heat of room temperature indefinitely.

The borax also acts upon the milk, in combination with the glycerine and formaldehyde, to render the compound viscous and stable and prevent the same from crystallizing and drying out.

The presence of milk, glycerine and borax in the compound renders the same viscous and nondrying and fortifies the glue against drying out.

The wax acts as a lubricant that prevents shrinkage and stickiness under heat which is generated when utilizing a member made of this compound for grinding or polishing purposes.

By varying the glycerine, wax and water content in the compound the density of the grinding or polishing member may be varied to make the same harder or softer to suit the same for grinding or polishing plastics and metals of varying degrees of hardness.

If desired sugar and soap in the amount mentioned may be added to this composition, the sugar aiding in rendering the compound flexible and the soap preventing tackiness of the grinding or polishing member and helping to expel the detritus therefrom.

In its finished condition this compound is sufficiently friable that a grinding or polishing member made of the same will wear away and still not be excessively tough to interfere with its proper grinding and polishing function.

As a Whole this compound has a high degree of pliability, elasticity and adhesiveness sufiicient to reliably cement the wool fibers and abrasive grains together and retain the requisite cushion effect of the wheel or other member made of this compound.

Moreover the binding medium in this compound will not permit the detritus which is removed from the article being ground or polished to load up or cling tenaciously to the grinding or polishing member, but instead will throw off or unload such detritus from this member and maintain the working surface constantly in a clean sharp condition and thus avoid the necessity of frequent dressing of this member for maintaining the same in a high state of efficiency.

In polishing and grinding members, as heretofore constructed of solid carborundum, emery or other abrasive, the working surface of such members becomes loaded or glazed with detritus or particles removed from the article being ground or polished by the impact of this member with said article, especially when working on softer metals and plastics.

Inasmuch as the wool fibers are intimately distributed among the sharp abrasive grains a cushioning efiect is produced during impacts of the grinding or polishing member against the article being treated which has the effect of loosening the removed particles and causing the same to fall off or be thrown off the polishing or grinding member and thus automatically maintain the latter in good working condition without necessitating any dressing or cutting down operation for this purpose.

I claim as my invention:

1. The method of making a non-loading, resilient, abrasive grinding member, which comprises spreading a layer of wool in a fluffy state on a warm surface, spreading abrasive grains over said layer, applying a heat curing liquid adhesive binder to said layer and grains to thoroughly wet the same, folding said layer over, tamping said folded layer to felt said wool and incorporate said adhesive binder and grains as a homogeneous mass, filling a mold with said mass, heating said mold to cure said adhesive, and removing said mass from said mold.

2. The method of making a non-loading, resilient, abrasive grinding member, which comprises spreading a layer of wool in a fluffy state on a warm surface, spreading abrasive grains over said layer, applying an aqueous mixture of animal glue, glycerine, borax, casein and ceresin wax to said layer and grains to thoroughly wet the same, folding said layer over, tamping said folded layer to felt said Wool and incorporate said aqueous mixture and grains as a homogeneous mass, applying formaldehyde to said mass, filling a mold with said mass, heating said mold to about F. for about five hours to cure said aqueous mixture, and removing said mass from said mold and drying thesame.

FREDERICK H. APEL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 290,368 Sperry Dec. 18, 1883 305,139 Boynton et al Sept. 16, 1884 684,710 Olson Oct. 15, 1901 799,200 Slager Sept. 12, 1905 1,302,320 Damon Apr. 29, 1919 1,693,697 Hafner Dec. 4, 1928 1,777,162 Biddle Sept. 30, 1930 1,814,768 Rippey et al July 14, 1931 2,062,671 Lupo Dec. 1, 1936 2,191,803 Oesterle Feb. 27, 1940 2,129,377 Libovitz et a1 Sept. 6, 1938 2,325,180 Egeberg July 27, 1943 2,334,572 Melton et al Nov. 16, 1943 

